21261332116 has 12 divisors (see below), whose sum is σ = 38114827380. Its totient is φ = 10371381440.

The previous prime is 21261332111. The next prime is 21261332117. The reversal of 21261332116 is 61123316212.

It can be written as a sum of positive squares in 2 ways, for example, as 11029200400 + 10232131716 = 105020^2 + 101154^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21261332111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64820971 + ... + 64821298.

It is an arithmetic number, because the mean of its divisors is an integer number (3176235615).

Almost surely, 2^21261332116 is an apocalyptic number.

It is an amenable number.

21261332116 is a deficient number, since it is larger than the sum of its proper divisors (16853495264).

21261332116 is a wasteful number, since it uses less digits than its factorization.

21261332116 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129642314 (or 129642312 counting only the distinct ones).

The product of its digits is 2592, while the sum is 28.

Adding to 21261332116 its reverse (61123316212), we get a palindrome (82384648328).

The spelling of 21261332116 in words is "twenty-one billion, two hundred sixty-one million, three hundred thirty-two thousand, one hundred sixteen".